From: Dave Olien <dmo@osdl.org>

Christoph submitted a patch to linus last week fixing up some DAC960 driver
entry points.  That patch will OOPS during boot on version 2 controller
types.  Christoph's version of the disk_size() function was dereferencing
a NULL pointer in it's "else" clause.

Christoph's patch hasn't appeared in linus's BK tree yet.  So, I'm
resending Christoph's orignal patch with my fix to disk_size() included.
This patch can be applied to the driver in Linus's BK tree from April 28.

Here's Christoph's original description of his patch:

Some grepping showed that DAC960's open routine was duplicating parts
of check_disk_change().  I went on fixing this by implementing a
media_changed method and making DAC960_Open use it.  While looking
at the surrounding code I noticed that

  (a) all methods weren't using the private data the upperlayer
      hands to it properly, but instead using kdev_t-based indexes
  (b) DAC960_Open/DAC960_Release was keeping never used counters
  (c) DAC960_Open was doing tons of checks the upperlayer already does
  (d) DAC960_Release was entirely superflous.

The patch below corrects that and rewrites the block entry points
into readable code - 100 LOC are gone and the same amount replaced
by readable code.